A. Field of the Invention
The present invention relates to a transportation mechanism of magnetic handling for accessing Compact Disks, in particular, to a transportation mechanism with an electromagnetic attraction means used in the manufacturing of Compact Disks.
B. Description of the Related Art
In the manufacturing of Compact Disks like CD-ROM, DVD, and so on, a transportation mechanism is needed for conveying Compact Disks (hereafter referred to as CD) from one process to another. FIG. 1A is a schematic view of a conventional transportation mechanism provided with three suction heads by a vacuum for CDs and FIG. 1B is an enlarged front view of the suction head.
As shown in FIGS. 1A and 1B, a conventional transportation mechanism 100 of CDs includes a transporting arm 101, and a base 102 mounted at the transporting arm 101 and having a plurality of vacuum suction heads 103 for CDs. A typical suction head for a conventional vacuum chuck has vacuum ducts (not shown) connected together in the form of perforations or grooved channels including perforations. The cross-sectional area of suction determined by the overall perforations is somehow limited that the holding force exerted on the workpiece is hardly sufficient. As shown in FIG. 1A for the operation of the conventional suction head 103 by a vacuum, a vacuum pump (not shown) is powered on when the suction heads 103 are moved by the transporting arm 101 toward a feed portion of the non-information zone of the CD 104, then the suction heads 103 is caused to attract the CD 104 by the pressure difference between inside and outside of the vacuum ducts, and the CD 104 is further moved by the transporting arm 101 to a position for a manufacturing process and is further released by breaking up the vacuum of the vacuum ducts.
In general, the vacuum suction head is used for conveying the small-sized component of different processes, such as the electronic component being placed onto a printed circuit board. As for the manufacturing of CDs, the cross-sectional area of the vacuum suction head should be as large as possible to obtain the maximum sucking area in the non-information zone of the CD. However, compared to the normal-sized CD (120 mm), the mini-sized CD (32 mm) has a much smaller non-information zone such that the information zone surrounding the central opening of the CD is much easier to be unintentionally scratched by the suction head because of the limited sucking area of the suction head. Moreover, the attraction force provided by the conventional suction head of vacuum ducts is barely sufficient for a CD which is much heavier than the usual workpiece like the electronic component such that the CD chucked by a vacuum suction is much easier to be dropped accidentally during the transporting of manufacturing processes, thereby reducing the production yield. Besides, CDs are dropped more frequently during transportation because of the particle contamination due to the insufficient vacuum in ducts since such costly and complicated design is easy to be damaged in operation and difficult for maintenance.
One of the objects of the invention is to provide a transportation mechanism of magnetic handling by means of electromagnetic attraction for accessing CDs; the transportation mechanism includes a reciprocating device having a base, an electromagnetic head provided on the base, a control unit controlling the movement of the reciprocating device, and a magnetic spacer. The CD, sandwiched by the electromagnetic suction head and the magnetic spacer as the magnetic spacer is attracted by the electromagnetic head, is further transported by the transportation mechanism whereby the damage due to bad suction for CDs is minimized. In comparison with the conventional suction means by vacuum, the transportation mechanism of the invention is also advantaged for the simple structure, easy maintenance, and low cost, thereby raising the manufacturing yield.